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varycoef (version 0.3.2)

init_bounds_optim: Setting of Optimization Bounds and Initial Values

Description

Sets bounds and initial values for optim by extracting potentially given values from SVC_mle_control and checking them, or calculating them from given data. See Details.

Usage

init_bounds_optim(control, p, q, id_obj, med_dist, y_var, OLS_mu)

Arguments

control

(SVC_mle_control output, i.e. list)

p

(numeric(1)) Number of fixed effects

q

(numeric(1)) Number of SVCs

id_obj

(numeric(2*q+1+q)) Index vector to identify the arguments of objective function.

med_dist

(numeric(1)) Median distance between observations

y_var

(numeric(1)) Variance of response y

OLS_mu

(numeric(p)) Coefficient estimates of ordinary least squares (OLS).

Value

A list with three entries: lower, init, and upper.

Details

If values are not provided, then they are set in the following way. Let \(d\) be the median distance med_dist, let \(s^2_y\) be the variance of the response y_var, and let \(b_j\) be the OLS coefficients of the linear model. The computed values are given in the table below.

Parameter Lower bound Initial Value Upper Bound
Range \(d/1000\) \(d/4\) \(10 d\)
Variance \(0\) \(s^2_y/(q+1)\) \(10s^2_y\)
Nugget \(10^{-6}\) \(s^2_y/(q+1)\) \(10s^2_y\)
Mean \(j\) -Inf \(b_j\) Inf